What is glaucoma?
Glaucoma is a group of diseases that damage the optic nerve, which brings vision signals from the eye to the brain. Glaucoma usually occurs because pressure within the eyeball is too high. Vision loss can almost always be prevented if the eye pressure is lowered substantially and consistently. Since consistently low pressure is protective, it is important for patients to take their drops regularly.

Excessive eyeball pressure is the commonest cause of glaucoma, but others important factors include:

1. poor blood flow to the optic nerve due to low blood pressure, aggressive treatment of high blood pressure, or blood vessel spasm; vessel spasm can occur in patients with migraine or Raynaud’s (a condition in which hands turn blue in cold weather)

2. a structurally weak nerve, due to high myopia or other hereditary factors

3. low brain pressure (cerebro-spinal fluid pressure); this makes it easier for eyeball pressure to deform the optic nerve back towards the brain

There are many different types of glaucoma with open-angle glaucoma as the most common form.

What are the symptoms of glaucoma?
In its early stages, glaucoma has no symptoms. As the disease progresses and more damage occurs, blind spots develop in your peripheral (side) vision. These spots may not be noticeable until the optic nerve has become severely damaged — or until detected by an ophthalmologist during a complete exam.

People at risk for closed-angle glaucoma, where the eye’s drainage angle becomes blocked, usually have no symptoms before the attack, though some early symptoms can include blurred vision, halos, headache or mild eye pain or redness. At the time of a closed-angle glaucoma attack, symptoms include:

• Severe eye or brow pain;
• Redness of the eye;
• Decreased or blurred vision;
• Seeing colored rainbows or halos;
• Headache;
• Nausea;
• Vomiting.

People with “normal-tension glaucoma” may have eye pressures within normal ranges, but have glaucoma signs and symptoms, such as blind spots in their field of vision and optic nerve damage.

Some people may not have glaucoma symptoms, but may have higher than normal eye pressure (called ocular hypertension). They are considered “glaucoma suspects,” and should be monitored carefully by an ophthalmologist.

For more information, please visit
http://www.geteyesmart.org/eyesmart/diseases/glaucoma.cfm